The eight-year bull market in U.S. equities lives on but is getting "rather old in the tooth," according to investor Dennis Gartman, who has warned about how quick a fall could be once it comes.
The editor and publisher of Gartman Letter observed that years spent on the trading floor has taught him that, "stuff goes down a whole lot faster than stuff goes up."
Explaining on CNBC Wednesday why this week's spike in the VIX index (measure of equity market volatility) didn't precipitate a fall in major U.S. equity markets, Gartman noted that the assumption that volatility only measured downside risk was flawed and that markets were beginning to acknowledge that.
"What we're seeing now is the VIX beginning to understand you can have volatility in both directions," he said, clarifying that the VIX is not a measure of bearishness or bullishness but volatility.
"There are geopolitical circumstances out there that are very disturbing … And I think the market wants to price that in," he added, referring to the VIX's 17 percent move higher in the first two trading days of this week.